Macroazo compound, a process for its production, a macroazo initiator, and a process for its use

ABSTRACT

An azoamide compound of the formula: ##STR1## wherein R 1  through R 4  are independently an alkyl group; X is an alkylene groupl Y is --O-- or --NH--; and n is an integer of 2 or more, is effective for producing a macroazo compound, which is a useful initiator for producing block copolymers.

This is a Divisional Application of application Ser. No. 08/888,625,filed Jul. 7, 1997, which issued as U.S. Pat. No. 5,854,406 on Dec. 29,1998. The entire disclosure of the prior application is herebyincorporated by reference herein in its entirety.

BACKGROUND OF TEE INVENTION

The present invention relates to an azoamide compound excellent in thesolubility in various solvents and useful as a polymerization initiatorand the like; and to a novel macroazo compound having in one moleculetwo types of azo groups different from each other in the decompositionactivity.

In the recent years, polymeric compounds have progressed from generalpurpose polymer to functional polymer, and block polymers which can beexpected to manifest various functions effectively are being watchedwith interest. In such a state of things, an attempt to prepare a blockpolymer by the use of an azo compound was proposed, and a straight chainhigh-polymeric azo compound having a plurality of azo groups on the mainchain obtained through an alternating polycondensation of an azocompound and a bifunctional compound was reported in JP-A-64-62318.However, the polymeric azo compounds reported in the above-mentionedpatent gazette were made of a single azo compound, and therefore the azogroups existing on the main chain are all identical with each other inthe decomposition activity. Thus, in order to leave a desired portion ofthe azo groups undecomposed in the first step of polymerization and touse the undecomposed portion of azo group in the second step ofpolymerization, it was necessary to control the temperature and time ofpolymerization strictly in the first step of polymerization. Further,the starting azo compound was inferior in solubility, so that nosufficient function as a polymerization initiator could be exhibited.

With the aim of solving these problems, an azo compound obtained bysubjecting two kinds of azo compounds different in decompositionactivity to a condensation reaction was reported (U.S. Pat. Nos.3,763,129, No. 3,868,359, No. 3,649,614, No. 3,956,269, etc.). Such azocompounds, however, had at most 2 or 3 azo groups in one molecule, andtherefore when such an azo compound was used as a polymerizationinitiator, the following difficulties arose: (1) a polymer of highmolecular weight was difficult to obtain, (2) when the number of azogroups was 2, only an AB type polymer could be obtained, while when thenumber of azo group was 3, only an ABA type polymer could be obtained (Ais a segment derived from a monomer A and B is a segment derived from amonomer B, hereinafter the same), (3) a number of radicals derived fromthe initiator, not participating in the polymerization, were formed, and(4) the kind of monomer which can be polymerized by this method waslimited, because the azo compound was low in solubility in itself.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide a novel azo compound excellent in solubility in varioussolvents, and to provide a novel macroazo compound obtained from saidazo compound and excellent in solubility in various solvents, saidmacroazo compound being usable as a macroazo initiator for producing ablock polymer easily and in a high efficiency without needing any strictcontrol.

The present invention provides an azoamide compound represented by thefollowing formula: ##STR2## wherein R¹ to R⁴ are independently an alkylgroup; X is an alkylene group; Y is O or NH provided that a plurality ofY may be the same or different; and n is an integer of 2 or more.

The present invention also provides a process for producing theabove-mentioned azoamide compound which comprises reacting anazodicarboxylic acid diester compound represented by the followingformula: ##STR3## wherein R⁹ is a lower alkyl group; and R¹ to R⁴ are asdefined above, with an aminoalcohol or a diamine represented by thefollowing formula:

    H.sub.2 N--(X--Y).sub.n --H                                [4]

wherein X, Y and n are as defined above.

The present invention further provides a polymerization initiatorcomprising the above-mentioned azoamide compound, a polymerizationprocess using said polymerization initiator, a macroazo compoundobtained by said polymerization process, and a polymerization process ofa monomer using said macroazo compound.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an azoamide compound represented by thefollowing formula: ##STR4## wherein R¹ to R⁴ are independently an alkylgroup; X is an alkylene group; Y is O or NH provided that a plurality ofY may be the same or different; and n is an integer of 2 or more.

The present invention further relates to a process for producing theabove-mentioned azoamide compound which comprises reacting anazodicarboxylic acid diester compound represented by the followingformula: ##STR5## wherein R⁹ is a lower alkyl group; and R¹ to R⁴ are asdefined above, with an aminoalcohol or a diamine represented by thefollowing formula:

    H.sub.2 N--(X--Y).sub.n --H                                [4]

wherein X, Y and n are as defined above.

The present invention further relates to a polymerization initiatorcomprising the above-mentioned azoamide compound.

The present invention further relates to a process for polymerizationwhich comprises using the above-mentioned azoamide compound as apolymerization initiator.

The present invention further relates to a macroazo compound constitutedof repeating units represented by the following formula: ##STR6##wherein R⁵ and R⁷ are independently an alkyl group; R⁶ and R⁸ areindependently an alkyl group or a cyano group; T is an alkylene group;and R¹ to R⁴, X, Y and n are as defined above; provided that the degreeof polymerization of said macroazo compound is 2 or more.

The present invention further relates to a process for producing amacroazo compound which comprises reacting the above-mentioned azoamidecompound with an azodicarboxylic acid compound represented by thefollowing formula: ##STR7## wherein R⁵ and R⁷ are independently an alkylgroup; R⁶ and R⁸ are independently an alkyl group or a cyano group; T isan alkylene group; and E is a hydroxyl group or Z; and Z is a halogenatom.

The present invention further relates to a macroazo initiator comprisingthe above-mentioned macroazo compound.

The present invention further relates to a process for polymerizationwhich comprises using the above-mentioned macroazo initiator.

The present invention further relates to a process for producing a blockpolymer which comprises using the above-mentioned macroazo initiator.

The alkyl group represented by R¹ to R⁴ in the formulas [1], [2] and [3]and the alkyl group represented by R⁵ to R⁸ in the formulas [2] and [7]may be any of straight chain, branched chain and cyclic alkyl groups, ofwhich examples are lower alkyl groups such as alkyl groups having 1-6carbon atoms. Specific examples thereof include a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, anisobutyl group, a tert-butyl group, a sec-butyl group, a n-pentyl group,an isopentyl group, a neopentyl group, a tert-pentyl group, a3,3-dimethylbutyl group, a 1,1-dimethylbutyl group, a 1-methylpentylgroup, a n-hexyl group, an isohexyl group, a cyclopropyl group, acyclopentyl group, a cyclohexyl group and the like.

The alkylene group represented by X in the formulas [1], [2] and [4] maybe any of straight chain, branched chain and cyclic alkylene groups, ofwhich examples are alkylene groups having 1-10 carbon atoms. Specificexamples thereof include a methylene group, an ethylene group, apropylene group, a butylene group, a 2-methylpropylene group, apentylene group, a 2,2-dimethylpropylene group, a 2-ethylpropylenegroup, a hexylene group, a heptylene group, an octylene group, a2-ethylhexylene group, a nonylene group, a decylene group, acyclopropylene group, a cyclopentylene group, a cyclohexylene group andthe like. Of these alkylene groups, particularly preferred are alkylenegroups having 1-6 carbon atoms. The groups represented by X which arepresent in the number of n may be identical with or different from oneanother. Y is O or NH, and a plurality of groups represented by Y, whichis present in the number of n, may be identical with (only O or NH) ordifferent from one another (O and NH being present). The number n isusually 2 or more and, preferably 2-50, and more preferably 2-30,further preferably 2-10, and most preferably 2-4.

The alkylene group represented by T in the formulas [2] and [7] may beany of straight chain, branched chain and cyclic alkylene groups, ofwhich examples are alkylene groups having 1-10 carbon atoms. Specificexamples thereof include a methylene group, an ethylene group, apropylene group, a butylene group, a 2-methylpropylene group, apentylene group, a 2,2-dimethylpropylene group, a 2-ethylpropylenegroup, a hexylene group, a heptylene group, an octylene group, a2-ethylhexylene group, a nonylene group, a decylene group, acyclopropylene group, a cyclopentylene group, a cyclohexylene group andthe like. Of these alkylene groups, particularly preferred are alkylenegroups having 1-6 carbon atoms.

The lower alkyl group represented by R⁹ in the formula [3] may be any ofstraight chain and branched chain alkyl groups, of which examples arealkyl groups having 1-6 carbon atoms. Specific examples thereof includea methyl group, an ethyl group, a n-propyl group, an isopropyl group, an-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group,a n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentylgroup, a 3,3-dimethylbutyl group, a 1,1-dimethylbutyl group, a1-methylpentyl group, a n-hexyl group, an isohexyl group and the like.

As the halogen atom represented by Z in the definition of E in theformula [7], fluorine, chlorine, bromine, iodine and the like can bereferred to.

The azoamide compound represented by the above-mentioned formula [1] canbe produced in the following manner.

That is, the azoamide compound can easily be obtained by reacting anazodicarboxylic acid diester compound represented by the followingformula: ##STR8## wherein R¹ to R⁴ and R⁹ are as defined above, with anaminoalcohol or a diamine represented by the following formula:

    H.sub.2 N--(X--Y).sub.n --H                                [4]

wherein X, Y and n are as defined above, in an appropriate solvent or inthe absence of solvent, in the presence of an alkaline organic metalcompound.

As the alkaline organic metal compounds which can be used in theproduction of the azoamide compound of the present invention, alkalimetal alkoxides such as sodium methoxide, sodium ethoxide, potassiummethoxide, potassium ethoxide, potassium tert-butoxide and the like; andorganic lithium compounds such as n-butyllithium, tert-butyllithium andthe like can be referred to.

The alkaline organic metal compound is used usually in an amount of0.05-3 equivalents and preferably 0.1-0.5 equivalent per equivalent ofazodicarboxylic acid diester compound, though the amount of the alkalineorganic metal compound may vary depending on the kind of aminoalcohol ordiamine.

The reaction solvents which can be used include hydrocarbons such astoluene, xylene, benzene, cyclohexane, n-hexane, n-octane and the like;alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol,isobutanol, tert-butanol and the like; dimethylformamide, dimethylsulfoxide, and the like. These solvents may be used singly or as amixture thereof.

The amounts of the azodicarboxylic acid diester compound and theaminoalcohol (or diamine) used for production of the azoamide compoundof the present invention vary depending on the kind of aminoalcohol (ordiamine). However, the amount of the aminoalcohol (or diamine) isusually appropriately selected from a range of from 1.5 moles to 10moles and preferably from a range of from 2 moles to 5 moles, per moleof the azodicarboxylic acid diester compound.

The reaction temperature is not particularly limited. If the reactiontemperature is too high, however, decomposition of the azo group takesplace. If the reaction temperature is too low, the reaction velocity islow and the production takes a long period of time. Accordingly, thereaction temperature is usually appropriately selected from a range offrom 0° C. to 40° C.

The reaction time varies dependently on the kinds of the azodicarboxylicacid diester compound and the aminoalcohol (or diamine). Usually,however, the reaction time is appropriately selected from a range offrom 1 hour to 24 hours.

As the azodicarboxylic acid diester compound and the aminoalcohol (ordiamine) used in the present invention, commercial products may be used,and those produced appropriately according to the usual methods may alsobe used.

Since the azoamide compound thus obtained easily generates radicalspecies with evolution of nitrogen gas by cleavage of azo groups uponheating or photo-irradiation, polymerization proceeds rapidly even ifany of various monomers are present.

For polymerizing or copolymerizing a monomer by using the azoamidecompound of the present invention as a polymerization initiator, thefollowing procedure may be adopted, for example.

Thus, the azoamide compound of the present invention represented by theformula [1] and a monomer are subjected to a polymerization reactionaccording to the usual method in an appropriate solvent or in theabsence of solvent, and optionally in the atmosphere of an inert gas.

After the reaction, a post-treatment and the like may be carried outaccording to the conventional procedures in this field of art.

If necessary, a chain transfer agent such as laurylmercaptan,octylmercaptan, butylmercaptan, 2-mercaptoethanol, butyl thioglycolateor the like may be added to the polymerization system in order tocontrol the molecular weight.

As the monomer, vinyl monomers, diene monomers and the like can bereferred to, for example.

Specific examples of the vinyl monomer include α-ethylenically aromatichydrocarbons having 8-20 carbon atoms such as styrene, 4-methylstyrene,4-ethylstyrene, 4-methoxystyrene, divinylbenzene and the like; vinylesters having 3-20 carbon atoms such as vinyl formate, vinyl acetate,vinyl propionate, isopropenyl acetate and the like; halogen-containingvinyl compounds having 2-20 carbon atoms such as vinyl chloride,vinylidene chloride, vinylidene fluoride, tetrafluoroethylene,tetrachloroethylene and the like; ethylenic carboxylic acids having 3-20carbon atoms such as acrylic acid, methacrylic acid, itanocnic acid,maleic acid, fumaric acid, crotonic acid, citraconic acid, methaconicacid, vinylacetic acid, allylacetic acid, vinylbenzoic acid and the like(these acids may be used in the form of a salt of alkali metal such assodium, potassium and the like or ammonium salt, if necessary);ethylenic carboxylic esters having 4-20 carbon atoms such as methylmethacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearylmethacrylate, vinyl methacrylate, allyl methacrylate, phenylmethacrylate, benzyl methacrylate, methyl acrylate, ethyl acrylate,butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearylacrylate, vinyl acrylate, dimethyl itaconate, diethyl itaconate,dimethyl maleate, diethyl maleate, dimethyl fumarate, diethyl fumarte,methyl crotonate, ethyl crotonate, vinyl crotonate, dimethylcitraconate, diethyl citraconate, dimethyl methaconate, diethylmethaconate, methyl 3-butenoate, 2-hydroxyethyl methacrylate,3-hydroxypropyl methacrylate, 2-hydroxypropyl methacrylate,2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxypropylacrylate and the like; cyano-containing vinyl compounds having 3-20carbon atoms such as acrylonitrile, methacrylonitrile, allyl cyanide andthe like; vinyl amide compounds having 3-20 carbon atoms such asacrylamide, methacrylamide and the like; ethylenic aldehydes having 3-20carbon atoms such as acrolein, crotonaldehyde and the like;vinylsulfonic acids having 2-20 carbon atoms such as vinylsulfonic acid,4-vinylbenzene-sulfonic acid and the like (these acids may be used inthe form of a salt of alkali metal salt such as sodium, potassium andthe like, if necessary); vinyl aliphatic amines having 2-20 carbon atomssuch as vinylamine, allylamine and the like; vinyl aromatic amineshaving 8-20 carbon atoms such as vinylaniline and the like; vinylaliphatic heterocyclic amines having 5-20 carbon atoms such asN-vinylpyrrolidone, vinylpiperidine and the like; vinyl aromaticheterocyclic amines having 5-20 carbon atoms such as vinylpyridine,1-vinylimidazole and the like; ethylenic alcohols having 3-20 carbonatoms such as allyl alcohol, crotyl alcohol and the like; and ethylenicphenols having 8-20 carbon atoms such as 4-vinylphenol and the like.

Specific examples of the diene monomer include diene compounds having4-20 carbon atoms such as butadiene, isoprene and the like.

These monomers may be used either singly or in proper combinationthereof.

As the method of the polymerization, solution polymerization, bulkpolymerization, suspension polymerization, emulsion polymerization andthe like can be referred to.

The solvents which can be used in the solution polymerization are, forexample, ethers such as tetrahydrofuran, diethyl ether, dioxane and thelike; halogenated hydrocarbons such as chloroform, methylene chloride,1,2-dichloroethane, carbon tetrachloride, trichlorethylene and the like;hydrocarbons such as n-hexane, n-octane, cyclohexane, petroleum ether,toluene, benzene, xylene and the like; alcohols such as methanol,ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanoland the like; ketones such as acetone, methyl ethyl ketone, methylisobutyl ketone, cyclohexanone and the like; esters such as methylacetate, ethyl acetate, n-butyl acetate, methyl propionate and the like;acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide,N-methylpyrrolidone, dimethyl sulfoxide, water and the like. Thesesolvents may be used singly or as a mixture thereof.

The polymerization is preferably carried out in an atmosphere of inertgas. As the inert gas, nitrogen gas, argon gas and the like can bereferred to.

In the practice of the polymerization reaction, the amount of theazoamide compound may vary depending on the kind of monomer used.Generally speaking, however, the amount of azoamide compound may beselected from a wide range. The amount of azoamide compound is usuallyfrom 0.01 to 100% by weight and preferably from 0.05 to 50% by weight,based on monomer.

Although concentration of the monomer at the time of polymerization mayvary depending on the kind of monomer, it is appropriately selectedusually from a range of 5 to 100% by weight and preferably from a rangeof 10 to 60% by weight.

The temperature of polymerization is not particularly limited. However,if the temperature of polymerization is too low, decomposition of theazo group cannot take place sufficiently, so that the polymerizationprogresses too slowly. If the temperature of polymerization is too high,decomposition of the azo group takes place too violently, so that thepolymerization reaction is difficult to control. Accordingly, thetemperature of polymerization is appropriately selected usually from arange of 20-150° C. and preferably from a range of 50-130° C.

Although the reaction time varies dependently on the kinds of azoamidecompound and monomer and concentrations thereof, the reaction time isappropriately selected usually from a range of 2-24 hours.

The characteristic features of the azoamide compound of the presentinvention are as follows:

1) Since the azoamide compound of the present invention has reactivehydroxyl or amino group on the molecular terminal thereof, the azoamidecompound is excellent in solubility in various solvents.

2) Into the molecular terminal of the polymer obtained by using theazoamide compound as a polymerization initiator, a hydroxyl or aminogroup derived from the azoamide compound can be introduced, and therebyvarious functions can be imparted to the polymer.

3) Since the polymer has reactive hydroxyl (or amino) group on themolecular terminal thereof, a reaction of the hydroxyl or amino group ofsuch a polymer with a compound having reactive functional group can forma polymeric azo compound constituted of repeating units having many azogroups and excellent solubility.

4) Since the polymeric azo compound thus formed has an alkylene part inthe molecule thereof through intermediation of O or NH, the polymericazo compound is expected to be usable as an inclusion compound, ifnecessary.

The macroazo compound of the present invention constituted of therepeating unit represented by formula [2] can be produced from theazoamide compound of the present invention represented by formula [1],in the following manner.

Thus, one mole of the azoamide compound represented by formula [1] and1-1.2 moles, preferably an equimolar quantity, of an azodicarboxylicacid compound represented by the following formula [5]: ##STR9## whereinR⁵ to R⁸ and T are as defined above, (a compound of the above-mentionedformula [7] wherein E is a hydroxyl group) are subjected to apolycondensation reaction by the use of a dehydrating agent in anappropriate solvent, if necessary in the presence of a basic catalyst,and if necessary in an atmosphere of an inert gas, by which the macroazocompound of the present invention can be formed.

Alternatively, the macroazo compound of the present inventionconstituted of the repeating unit of the formula [2] can easily beformed by the following method, too.

Thus, in the first step, an azodicarboxylic acid compound represented bythe formula [5] is reacted with a halogenating agent in an appropriatesolvent or in the absence of solvent at 0-120° C. for 0.5-20 hours. Bythis reaction, there can be obtained an azodicarboxylic acid dihaliderepresented by the following formula [6]: ##STR10## wherein R⁵ to R⁸, Tand Z are as defined above (this compound is a compound of formula [7]wherein E is Z).

As said halogenating agent, thionyl chloride, thionyl bromide,phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride,phosphorus oxychloride, phosphorus oxybromide and the like can be used.

The amount of the halogenating agent is appropriately selected usuallyfrom a range of 1.5 to 10 moles and preferably 2 to 5 moles, per mole ofthe azodicarboxylic acid compound.

In the subsequent step, one mole of the azoamide compound represented bythe formula [1] and 1-1.2 moles, preferably an equimolar quantity, ofthe azodicarboxylic acid dihalide represented by the above-mentionedformula [6] are subjected to a polycondensation reaction in anappropriate solvent, if necessary in the presence of a basic catalyst,and if necessary in an atmosphere of an inert gas, by which the macroazocompound of the present invention can be obtained. The macroazo compoundof the present invention thus obtained has a carbonyl halide group onone molecular terminal thereof (when the azoamide compound of theformula [1] is reacted with the azodicarboxylic acid compoundrepresented by the formula [5], the product has a carboxyl group on onemolecular terminal thereof). If necessary, the carbonyl halide grouppresent on one molecular terminal can be converted to a carboxyl groupby hydrolyzing the macroazo compound in the conventional manner.

In any of these two methods, the reaction solvents which can be usedinclude ethers such as diethyl ether, diisopropyl ether,tetrahydrofuran, dioxane, dimethoxyethane and the like; halogenatedhydrocarbons such as carbon tetrachloride, chloroform, methylenechloride, 1,2-dichloroethane, trichlorethylene and the like;hydrocarbons such as n-hexane, benzene, toluene, xylene and the like;esters such as ethyl acetate, butyl acetate, methyl propionate and thelike; acetonitrile, N,N-dimethylformamide and the like. These solventsmay be used either singly or as a mixture thereof.

The first method uses a dehydrating agent. The dehydrating agent is notparticularly limited, so far as it is usable as a dehydrating condensingagent. Specific examples of said dehydrating agent include inorganicdehydrating agents such as concentrated sulfuric acid, diphosphoruspentoxide, anhydrous zinc chloride and the like; carbodiimides such asdicyclohexylcarbodiimide, diisopropylcarbodiimide,1-ethyl-3-(3-dimethylaminopropylcarbodiimide) hydrochloride and thelike; polyphosphoric acid, acetic anhydride, carbonyldiimidazole,p-toluenesulfonyl chloride and the like.

The amount of the dehydrating agent is not particularly limited.However, if the amount of the dehydrating agent is too small, thereaction progresses too slowly. The use of too large an amount ofdehydrating agent, however, is uneconomical. Thus, the amount of thedehydrating agent is appropriately selected usually from a range of 1 to5 moles and preferably from a range of 2 to 3 moles, per mole of theazoamide compound.

The polycondensation reaction is preferably carried out in the presenceof a basic catalyst. Specific examples of said basic catalyst includeorganic amines such as triethylamine, diisopropylethylamine,N,N-dimethylaniline, piperidine, pyridine, 4-dimethylaminopyridine,1,5-diazabicyclo[4.3.0]nona-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene,tri-n-butylamine, N-methylmorpholine and the like; metal hydrides suchas sodium hydride and the like; and basic alkali metal compounds such asn-butyllithium, tert-butyllithium and the like.

The amount of the basic catalyst is appropriately selected usually froma range of 0.5-5 moles and preferably from a range of 1-2 moles, permole of the azoamide compound.

If necessary, the polycondensation reaction may be carried out in anatmosphere of an inert gas. As the inert gas, nitrogen gas, argon gasand the like can be used.

The reaction temperature is not particularly limited. However, if thereaction temperature is too high, decomposition of the azo group ispromoted. If the reaction temperature is too low, the velocity ofreaction is low and the production takes too long a period of time.Thus, the reaction temperature is appropriately selected usually from arange of -10° C. to 60° C. If necessary, the reaction temperature may bestep-wise elevated from a low temperature. Although the reactiontemperature varies depending on the method of production, it isappropriately selected usually from a range of 1-60 hours.

The objective product may be isolated from the reaction mixture by anappropriate method in accordance with the kinds and quantities ofstarting materials, basic catalyst, dehydrating agent and solvent, andthe state of reaction mixture. For example, when the reaction mixture isa viscous liquid, the reaction mixture is diluted with an appropriatesolvent and filtered to remove the impurities and thereafter the solventis distilled off. In these manners, the objective macroazo compound isobtained.

As the azodicarboxylic acid compounds represented by the formula [5],any of commercially available products and those appropriately producedaccording to conventional methods may be used.

The macroazo compound of the present invention thus prepared is anoligomer of which degree of polymerization p is usually 2 or above,preferably 2-100, and further preferably about 2-30.

Since the macroazo compound of the present invention easily generatesradical species with evolution of nitrogen gas by cleavage of azo groupsupon heating or photo-irradiation, polymerization proceeds rapidly evenif any of various monomers are present.

As is apparent from the above-mentioned formula [2], the macroazocompound of the present invention has two kinds of azo groups in themolecule thereof. The two kinds of azo groups are different from eachother in the decomposing activity, because one of the two kinds of azogroups is linked to a carbon atom to which an alkylene group is linkedthrough inter-mediation of an amide group, while the other kind of azogroup is linked to a carbon atom to which an alkylene group is linkeddirectly.

Accordingly, the macroazo compound of the A present invention ischaracterized in that it has two kinds of azo groups different from eachother in decomposing activity in the molecule thereof. When the macroazocompound of the present invention is used as a macroazo initiator, it ispossible to decompose the azo group of higher decomposing activitypreferentially while hardly decomposing the azo group of lowerdecomposing activity by appropriately selecting the conditions ofdecomposition, by which there can be obtained a polymer in which the azogroup of lower activity is left undecomposed. If a polymerization of thesecond step is carried out by the use of the remaining lower activityazo group, there can easily be obtained a block polymer block-wisecontaining different monomer constituents.

Production of the block polymer using the macroazo compound as amacroazo initiator can be practiced in the following manner, forexample.

Thus, in the first step, the macroazo compound of the present inventionrepresented by the formula [2] and a monomer are subjected to apolymerization reaction in the usual manner in an appropriate solvent orin the absence of solvent, if necessary in an atmosphere of inert gas,under such a condition as to preferentially decompose the azo group ofhigher activity while hardly decomposing the azo group of loweractivity. Thus, an azo group-containing polymer can be obtained.

In the second step, the azo group-containing polymer and a monomerdifferent from the monomer used in the first step are subjected to apolymerization reaction in the usual manner in an appropriate solvent orin the absence of solvent, if necessary in an atmosphere of an inertgas, by which the objective block polymer can be obtained.

After the reaction, a post-treatment and the like may be carried outaccording to the conventional procedures of after treatments in thisfield of art.

In carrying out the polymerization, a chain transfer agent such aslaurylmercaptan, octylmercaptan, butylmercaptan, 2-mercaptoethanol,butyl thioglycolate or the like may be added if necessary, for thepurpose of regulating the molecular weight.

As the method of polymerization, solution polymerization, bulkpolymerization, suspension polymerization, emulsion polymerization andthe like can be adopted.

As the monomers used in the first and second steps of thepolymerization, all the monomers which can be used in -thepolymerization or copolymerization using the azoamide compound of thepresent invention as a polymerization initiator can be used.

As the solvent used in the solution polymerization, all the solventswhich have been mentioned above as solvents usable in the polymerizationor copolymerization of monomer by the use of the azoamide compound ofthe present invention can be referred to.

The polymerization is preferably carried out in an atmosphere of inertgas. As the inert gas, nitrogen gas, argon gas and the like can bereferred to.

Although the amount of the macroazo compound used in the polymerizationmay vary depending on the kind of monomer, it can be selected from awide range. The amount of the macroazo compound is appropriatelyselected from a range of 0.01-100% by weight and preferably from a rangeof 0.05-50% by weight, based on the monomer(s).

Although concentration of monomer in the polymerization reaction mayvary depending on the kind of monomer, it is appropriately selectedusually from a range of 5-100% by weight and preferably from a range of10-60% by weight.

Although the reaction temperature may be somewhat dependent on otherpolymerization conditions, it is usually selected from a range of 30° C.to 130° C. Preferably, the polymerization of the first step is carriedout at a low temperature and the polymerization of the second step iscarried out at a high temperature in order to obtain a block polymereffectively. The temperature of polymerization of the first step ispreferably in the range of 50° C. to 80° C., and the temperature ofpolymerization of the second step is preferably in the range of 80° C.to 120° C.

Although the reaction time may vary depending on the reactiontemperature, the kinds of azoamide compound and monomer to be reactedand the reaction conditions such as concentrations thereof, it isappropriately selected usually from a range of from 2 hours to 24 hours.

Generally speaking, high polymeric compounds cannot always be expressedby a simple structural formula because of complex structure. If theblock polymer obtained in the above-mentioned manner is daringlyexpressed by a structural formula, it can be expressed by the followingformula [8]:

    [--{(M).sub.a }--{(N).sub.b }--].sub.d                     [ 8]

because this polymerization reaction uses the macroazo compoundconstituted of a repeating unit of the above-mentioned formula [2] as amacroazo initiator, provided that M represents the unit derived from themonomer used in the polymerization of the first step, N represents theunit derived from the monomer used in the polymerization reaction of thesecond step, a and b each represents, independently of one another, anatural number, d represents an integer of at least 2, and {} embraces arandom structure such as graft copolymer structure, block copolymerstructure, etc.

In the above-mentioned manner, a block polymer can be produced easilyand quite efficiently by using the macroazo compound of the presentinvention as a macroazo initiator.

The macroazo compound of the present invention can be used not only as amacroazo initiator for production of block polymer successfully as hasbeen mentioned above, but also it can effectively be used as a radicalpolymerization initiator for polymerization of monomers, of course. Inthe radical polymerization using the macroazo compound of the presentinvention, the same monomers as used in the production of the blockpolymer can be used. As specific examples of said monomer, all themonomers previously mentioned as monomers usable for polymerization orcopolymerization using the azo compound of the present invention as apolymerization initiator can be referred to. The method ofpolymerization is also the same as that of conventional polymerizationusing a radical polymerization initiator.

Since the macroazo compound of the present invention is characterized inthat it can be used in the polymerization reactions using varioussolvents without trouble because of excellent solubility in variousorganic solvents.

Next, the present invention is explained in more detail with referenceto the following Examples and Experimental Examples. The presentinvention is by no means limited by these Examples.

EXAMPLE 1 Synthesis of2,2'-azobis[N-(2-hydroxyethoxy)-ethyl-2-methylpropionamide] ##STR11##

To a constantly stirred mixture comprising 23.0 g of dimethyl2,2'-azobis(2-methylpropionate) (V-601, a trade name, mfd. by Wako PureChemical Industries, Ltd., hereinafter referred to as "V-601"), 23.1 gof 2-(2-aminoethoxy)ethanol and 5 ml of methanol, 9.3 g of a 28 wt. %methanolic solution of sodium methoxide (hereinafter referred to as "28%CH₃ ONa") was added dropwise. The reaction was carried out with stirringat room temperature for 7 hours. After standing overnight, the reactionmixture was mixed with 50-ml of saturated sodium chloride solution, andextracted with 100 ml of dichloromethane. The organic layer was driedover anhydrous magnesium sulfate and the solvent was distilled off, andthere was obtained 28.8 g (yield 76%) of2,2'-azobis[N-(2-hydroxyethoxy)ethyl-2-methylpropionamide] as a lightyellow viscous liquid. 1H-NMR δ ppm (CDCl₃): 1.38 (s, 12H, ═N--C(CH₃)₂--), 2.77 (brs, 2H, --OH), 3.57 (m, 12H, --NH--CH₂ CH₂ OCH₂ CH₂ OH),3.71 (t, 4H, --O--CH₂ CH₂ --OH), 7.11 (brs, 2H, --CONH--).

UV (CH₃ OH): λ_(max) =375 nm. E (1%)=0.7569.

The temperature of 10-hour half life: 97° C.

EXAMPLE 2 Synthesis of Macroazo Compound ##STR12##

To a constantly stirred mixture comprising 11.2 g of4,4'-azobis(4-cyanopentanoic acid) (V-501, a trade name, mfd. by WakoPure Chemical Industries, Ltd., hereinafter referred to as "V-501"), 4.9g of 4-dimethylaminopyridine (DMAP), 15.1 g of the2,2'-azobis[N-(2-hydroxyethoxy)ethyl-2-methylpropionamide] obtained inExample 1 and 150 ml of dichloromethane, 18.2 g ofdicyclohexylcarbodiimide (DCC) was added. The reaction was carried outwith stirring at room temperature for 6 hours. After standing overnight,the resulting crystals were filtered off, and the filtrate was washedwith 100 ml of 10% hydrochloric acid solution and 150 ml of saturatedsodium chloride solution successively, and dried over anhydrousmagnesium sulfate. By distilling off the solvent, there was obtained20.2 g (yield 81.5%) of the objective compound as a yellow viscousliquid. A GPC measurement revealed that number-average molecular weightof this product was 6,650, and the degree of dispersion thereof was1.65. Hereinafter, this product is referred to as "MAI-l". ¹ H-NMR δ ppm(CDCl₃): 1.34 (s, 12H, ═N--C(CH₃)₂ --), 1.67-1.73 (d, 6H,═N--C(CH₃)(CN)--), 2.36-2.56 (m, 8H, CO--CH₂ CH₂ --), 3.58 (brs, 8H,--NH--CH₂ CH₂ OCH₂ CH₂ O--), 3.67 (brs, 4H, --NH--CH₂ CH₂ O--), 4.24(brs, 4H, COO--CH₂ CH₂ O--), 7.20 (brs, 2H, --CONH--).

UV (CH₃ OH); λ_(max) =363 nm. E (1%) =0.6324.

EXAMPLE 3 Production of Styrene-Methyl Methacrylate Block Polymer UsingMAI-l

(1) First Step, namely Polymerization of Styrene Using MAI-l

A mixture of 1.00 g of MAI-l obtained in Example 2, 25.30 g of styreneand 27.00 g of toluene was subjected to a polymerization reaction at 80°C. for 8 hours under a nitrogen stream . After the reaction, thereaction mixture was poured into methanol and precipitated. Thedeposited polymer was collected by filtration and dried to obtain 18.42g (yield 70.04%) of the objective azo group-containing polystyrene as awhite bulky product. The GPC measurement revealed that this product hada number-average molecular weight of 58,142, a weight-average molecularweight of 184,019, and a degree of dispersion of 3.17. Hereinafter, thisproduct is referred to as PSt*-[l].

(2) Step 2, namely Polymerization of Methyl Methacrylate Using PSt*-[l]

A mixture consisting of 10.01 g of the PSt*-[1] obtained in Paragraph(1), 20.02 g of methyl methacrylate and 100 ml of toluene was subjectedto a polymerization reaction under a nitrogen stream at 103° C. for 8hours. After the reaction, the reaction mixture was poured into methanoland precipitated. The polymer deposited was collected by filtration anddried to obtain 24.17 g (yield 80.49%) of the objective block polymer asa white fibrous product. A GPC measurement revealed that this producthad a number-average molecular weight of 61,020, a weight-averagemolecular weight of 147,251 and a degree of dispersion of 2.41. A ¹H-NMR measurement using CDCl₃ as a solvent for measurement revealed thatthe copolymer composition of this product was 63.33:36.67 as expressedin terms of styrene:methyl methacrylate ratio by weight.

Experimental Example 1 Solubility Test

The 2,2'-azobis[N-(2-hydroxyethoxy)ethyl-2-methylpropionamide](hereinafter referred to as "azoamide compound of the presentinvention") and MAI-l obtained in Example 2 were taken into a measuringflask. A variety of solvents were added to examine the solubility. Theresults are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Solvent       Azoamide compound                                                                             MAI-1                                           ______________________________________                                        Water         Soluble         Insoluble                                       Methanol      Soluble         Soluble                                         Acetonitrile  Soluble         Soluble                                         Methylene chloride                                                                          Soluble         Soluble                                         Ethyl acetate Soluble         Soluble                                         Toluene       Insoluble       Insoluble                                       Hexane        Insoluble       Insoluble                                       ______________________________________                                    

It is apparent from the results shown in Table 1 that the azoamidecompound of the present invention obtained in Example 1 is insoluble intoluene and hexane having a low polarity, and soluble in solvents ofwhich polarity is higher than that of toluene and hexane. Further, it isapparent that, the azoamide compound of the present invention is solublenot only in aqueous organic solvents such as methanol and the like butalso in non-aqueous organic solvents such as methylene chloride and thelike although the azoamide compound of the present invention is awater-soluble compound in itself. In other words, the azoamide compoundof the present invention obtained in Example 1 is explicitly excellentin solubility in various solvents.

On the other hand, it is apparent that the macroazo compound of thepresent invention obtained in Example 2 is insoluble in toluene andhexane having a low polarity, but it is soluble in solvents of whichpolarity is higher than that of toluene and hexane. It is further knownthat the macroazo compound of the present invention is soluble not onlyin aqueous organic solvents such as methanol and the like but also innon-aqueous organic solvents such as methylene chloride and the like,and therefore is excellent in solubility in various solvents.

EXAMPLE 4 Synthesis of2,2'-azobis[N-(2-hydroxy-ethylamino)ethyl-2-methylpropionamide]##STR13##

To a constantly stirred mixture comprising 23.0 g of V-601, 22.9 g of2-(2-aminoethylamino)ethanol and 5 ml of methanol, 4.7 g of 28% CH₃ ONawas added dropwise. The reaction was carried out with stirring at roomtemperature for 8 hours. After standing overnight, the reaction mixturewas mixed with 50 ml of saturated sodium chloride solution, andextracted with 100 ml of dichloromethane. The organic layer was driedover anhydrous magnesium sulfate and solvent was distilled off, andthere was obtained 29.8 g (yield 80%) of 2,2'-azobis[N-(2-hydroxyethylamino)ethyl-2-methylpropionamide ] of yellow viscousliquid.

¹ H-NMR δ ppm (CDCl₃): 1.39 (s, 12H,═N--C(CH₃)₂ --), 2.78 (m, 12H,--CONH--CH₂ CH₂ NHCH₂ CH₂ OH), 3.46 (m, 4H, --CONH--CH₂ CH₂ NH--), 3.65(t, 4H, --NH--CH₂ CH₂ OH), 7.14 (brs, 2H, --CONH--).

EXAMPLE 5 Synthesis of Macroazo Compound ##STR14##

To a constantly stirred mixture comprising 14.0 g of V-501, 6.1 g ofDMAP, 18.7 g of2,2'-azobis[N-(2-hydroxyethylamino)ethyl-2-methylpropionamide ] obtainedin Example 4 and 180 ml of dichloromethane, 22.7 g of DCC was added. Thereaction was carried out with stirring at room temperature for 8 hours.After standing overnight, deposited crystals were filtered off, and thefiltrate was poured into 600 ml of n-hexane to precipitate a macroazocompound. The solvent was removed by decantation, the precipitate wasdried under reduced pressure, and there was obtained 28.9 g (yield93.5%) of the objective compound as a light yellow product. A GPCmeasurement revealed that the number-average molecular weight of thisproduct was 2,390, and the degree of dispersion thereof was 1.45.

¹ H-NMR δ ppm (CDCl₃): 1.36 (brs, 12H, ═N--C(CH₃)₂), 1.72 (brs, 6H,═N--C(CH₃)(CN)--), 2.46 (brs, 18, --CH₂ CH₂ --COO--CH₂ CH₂ --NH--CH₂ C₂--), 3.51 (brs, 4H, --NH--CH₂ CH₂ NHCO--), 4.24 (brs, 4H, --COO--CH₂ CH₂--NH--), 7.44 (brs, 2H, --CONH--).

EXAMPLE 6

A styrene solution containing 4×10⁻⁴ mole/l. of the azoamide compoundobtained in Example 1 in an amount of 5 ml was charged in a glassampoule, and subjected to exhaust of the gas, followed by sealing underreduced pressure. A number of ampoules thus sealed were placed in aconstant temperature bath adjusted at 100° C. to initiate thepolymerization. After a certain time, an ampoule was taken out of theconstant temperature bath and cooled in ice water to terminate thepolymerization. Then the polymerization solution in the ampoule waspoured into methanol to deposit an polymer, which was filtered and driedat 60° C. for 6 hours under reduced pressure. The obtained polymer wasweighed. The conversion was obtained from the styrene amount at thecharge and the produced amount of the polymer. The results are shown inTable 2.

EXAMPLE 7

The process of Example 6 was repeated except for using the azoamidecompound obtained in Example 4 in place of the azoamide compoundobtained in Example 1. The conversion was obtained from the styreneamount at the charge and the produced amount of the polymer. The resultsare shown in Table 2.

                  TABLE 2                                                         ______________________________________                                        Example  Polymerization time (hours)                                          No.      1      2        3    4      5    6                                   ______________________________________                                        6        10.8   28.1     39.7 53.5   62.6 75.4                                7        5.5    18.5     32.3 40.6   48.9 58.1                                ______________________________________                                    

As is clear from Table 2, the azoamide compounds of the presentinvention obtained in Examples 1 and 4 have high polymerization activityin the polymerization of styrene.

As has been mentioned above, the present invention provides a novelazoamide compound excellent in solubility in various solvents. Thepolymer obtained by using said azoamide compound as a polymerizationinitiator has a hydroxyl group (or amino group) derived from theazoamide compound on the polymer molecular terminal thereof, andtherefore various functions can be given to the polymer. Thus, thepresent invention can contribute to the industry greatly. Further, thepresent invention provides a novel macroazo compound having two kinds ofazo groups different from each other in decomposing activity, in onemolecule. By carrying out a multi-step polymerization using the macroazocompound of the present invention, a block polymer block-wiseconstituted of different repeating units can be obtained efficiently.This is an outstanding effect of the present invention.

What is claimed is:
 1. A macroazo compound having repeating unitsrepresented by the following formula and having a degree ofpolymerization of at least 2: ##STR15## wherein R¹ to R⁵ and R⁷ areindependently an alkyl group; R⁶ and R⁸ are independently an alkyl groupor a cyano group; X and T are independently an alkylene group; Y is O orNH provided that each Y is the same or different; and n is an integer of2 or more.
 2. A process for producing an a macroazo compound of claim 1,which comprises reacting an azoamide compound represented by thefollowing formula: ##STR16## wherein R¹ to R⁴ are independently an alkylgroup; X is an alkylene group; Y is O or NH provided that each Y is thesame or different; and n is an integer of 2 or more, with anazodicarboxylic acid compound represented by the following formula:##STR17## wherein R⁵ and R⁷ are independently an alkyl group; R⁶ and R⁸are independently an alkyl group or a cyano group; T is an alkylenegroup; and E is a hydroxyl group or Z; and Z is a halogen atom.
 3. Amacroazo initiator comprising a macroazo compound of claim
 1. 4. Aprocess for producing a polymer, which comprises polymerizing a monomerin the presence of a macroazo initiator of claim
 3. 5. A processaccording to claim 4, wherein the monomer is a vinyl monomer.
 6. Aprocess for producing a block polymer, which comprises,in the firststep, polymerizing a monomer in the presence of a macroazo initiator ofclaim 3 to give an azo group-containing polymer, and then, in the secondstep, polymerizing a monomer different from that used in the first stepin the presence of the azo group-containing polymer.
 7. A processaccording to claim 6, wherein the monomer used in the first step is avinyl monomer, and that used in the second step is a vinyl monomerdifferent from that used in the first step.
 8. A process according toclaim 6, wherein the block polymer is styrene-methyl methacrylate blockpolymer.
 9. A macroazo compound according to claim 1, wherein R¹ to R⁵and R⁷ are independently an alkyl group having 1 to 6 carbon atoms; R⁶and R⁸ are a cyano group; X and T are independently an alkylene grouphaving 1 to 6 carbon atoms; Y is O or NH provided that each Y is thesame or different; and n is an integer of 2 to
 4. 10. A macroazocompound according to claim 1, which has repeating units represented bythe following formula: ##STR18##
 11. A macroazo compound according toclaim 1, which has repeating units represented by the following formula:12. A macroazo compound according to claim 1, wherein n is an integer offrom 2 to
 50. 13. A macroazo compound according to claim 1, where n isan integer of from 2 to
 30. 14. A macroazo compound according to claim1, wherein n is an integer of from 2 to
 10. 15. A macroazo compoundaccording to claim 1, wherein n is an integer of from 2 to
 4. 16. Amacroazo compound according to claim 1, said compound having a degree ofpolymerization of from 2 to
 100. 17. A macroazo compound according toclaim 1, said compound having a degree of polymerization of from 2 to30.
 18. A macroazo compound according to claim 1, said compound having adegree of polymerization of from 2 to 100.